Part of the problem in answering this question is that we don't get to see the after-marriage relationship very much within the context of the novel. We see the relationship of other marriages, and whether they are happy or not, based on love; however, the two main marriages that are made because of love--Jane and Bingley, and Elizabeth and Darcy--occur at the end of the novel and so we don't really get to see if the "happily ever after occurs." One would imply, however, that the marriages will be happy, since Austen went to great lengths to show examples of non-love marriages. For example, Lydia and Wickham's marriage, not based in love, was already strained when the newlywed couple came to visit the home. Lydia was giddy about being married, granted, but Wickham was restrained and tethered, and indifferent to his wife. Then, we have Charlotte and Mr. Collins, who, although they don't love each other, establish a domestic routine that they both can live with, even if not joyously. Through these negative examples, we can infer that Austen is saying that love would probably make things better, although not having love is survivable. She just liked to write about women who would not accept "survivable," and instead wanted "happy."
Given that Jane and Bingley do love each other, their marriage should hopefully be a bit more joyous. Jane loves Bingley, and Bingley loves Jane--they loved each other from the first, and only took so long in reuniting because of Darcy's well-intentioned but misguided meddlings in their relationship. Once all of that was resolved, however, Jane and Bingley were the picture of contentment and happiness. In all of Austen's novels, love plays a key role in the successful unitings of couples, and we can assume that in this case too. I hope that those thoughts helped; good luck!